[scarface74]

That’s exactly what you end up doing - writing your own rules engine instead of just using your language of choice.

How much harder is it to “deploy your whole” program than changing a complex XML/JSON configuration file or database change, testing it, and then deploying that?

In fact, it’s ususlly much easier deploying code. Setting up a simple pipeline to deploy a service is not rocket science.

[bartimus]

It makes sense to use a programming language for the rule logic. I'm just suggesting you need to conceptually separate the software code from the rule code. Have the rule code in a separate repository that can be deployed independently (by people with different roles). You can't just deploy new code. You'd perhaps want to apply previous versions of a rule.

In any case. The people maintaining/using the rules might not have a debugger available. They still need to have some kind of "rule stack trace" on how the system came to a certain answer.